The present invention relates to internal combustion engines of reciprocating piston type and is concerned with such engines which include one or more pistons, each of which is mounted to reciprocate in a respective cylinder and is pivotally connected to a connecting rod which is connected to a respective crank on a crankshaft, the connecting rod being pivotally connected to one end of an elongate link member which is pivotably connected to the associated crank at a point intermediate its ends and whose other end constitutes a rod which is restrained by a mounting such that it may pivot about a pivotal axis parallel to the axis of the crankshaft. The invention is also particularly, though not exclusively, concerned with engines of the general type disclosed in EP-A-0591153.